The BGS Lexicon of Named Rock Units — Result Details

Millom Park Formation [Obsolete: use WB]

Computer Code: MPA Preferred Map Code: MPa
Status Code: Full
Age range: Abereiddian Stage (O2) — Caradoc Series (O4)
Lithological Description: [Obsolete: use WB] Dacitic lapilli-tuff and tuff. Mostly massive with some interbeds of parallel bedded tuff. Intruded by basalt, basaltic andesite and andesite and locally contains intercalated andesite lava.
Definition of Lower Boundary: Unconformity. Overlies less widely distributed older Formations (Po House and Whinney Bank) in the Borrowdale Volcanic Group and locally rests directly on the Skiddaw Group.
Definition of Upper Boundary: Parallel bedded tuffs of the Duddon Hall Formation.
Thickness: 1800-2600m
Geographical Limits: Beckfoot (SD 194 899) to Kirksanton (SD 140 807), south-east of Whicham Valley, Cumbria.
Parent Unit: none recorded or not applicable
Previous Name(s): A variety of local names [Obsolete Name and Code: Use MPA] (-1707)
Middle Tuffs [Obsolete Name and Code: Use MPA] (-405)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Millom Park, north of Millom, Cumbria. 
Reference Section  Between Knott Hill and Beckfoot. 
Reference(s):
British Geological Survey. 1994a. Duddon Bridge and Hallthwaites, SD18NE, Solid and Drift 1:10 000. (Keyworth, Nottingham: British Geological Survey.) 
Green, J F N, 1913. The older Palaeozoic succession of the Dudden Estuary. London, 23pp. 
British Geological Survey. 1994b. Millom Park, SD18SE, Solid and Drift, 1:10 000. (Keyworth, Nottingham: British Geological Survey.) 
Mathieson, N A, 1986 Geology, structure and geochemistry of the Ordovician volcanic succession in south west Cumbria. Unpublished Ph.D. thesis, University of Sheffield. 
Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable